One question has occurred to me. It seems that MH370 may (and I say MAY) have been following airways towards Perth. Would an MH 777 have had a Kuala Lumpur - Perth route stored in the FMC library?
Given that MAS fly a scheduled non-stop service from KUL-PER (MH125) I'd say there was an excellent chance that the route was available in the FMC.